Typically, direct high-pressure injection of internal combustion engines requires a pressurized fuel produced in high-pressure pumps. The fuel pressure in gasoline engines are typically between 200 and 350 bar. Common rail diesel engines achieve typically pressures of 1800 up to 3000 bar.
Therefore, housings for high-pressure pumps have been developed to encounter the high-pressure during operation of the high-pressure pump in the combustion chamber. Especially, in common rail diesel engines the requirements for such housings are very high due to the very high pressure. To improve the integration of high-pressure pumps into the combustion engine and combustion chamber, respectively, unit-pumps are known. Unit-pumps are lubricated by oil instead of fuel, in particular engine oil.
However, heating-up of in particular fuel during operation of the high-pressure pump is still a challenge. Thus, efforts are conducted to reduce the heating-up of oil or fuel and improve in particular lubricity within the high-pressure pump.
Consequently, there is a need to develop a high-pressure pump arrangement such that a heating-up of the high-pressure pump can be reduced, and thus, there is a high-pressure pump arrangement needed which is able to overcome the heating-up of fuel, in a simple and cost-efficient manner.